EXCAVATING MACHINERY USED IN LAND DRAINAGE. 15 



The ditch was about 18 feet in top width, 12 feet deep, and had 

 | to 1 slopes. It followed an' old creek bed for a large part of the 

 distance. The material excavated was a clay, though some rock was 

 also encountered. Based upon the given dimensions of the ditch, the 

 total excavation amounted to 295,000 cubic yards. Eighteen months 

 were required to complete the work. The cost was as follows: 



Operation: 



Labor $6, 310. 94 



Fuel 2, 210. 30 



Repairs : 



Labor 1, 380. 12 



Material 1, 136. 71 



Interest and depreciation 4, 067. 00 



15, 105. 07 

 Cost per cubic yard, $0.0512. 



Miscellaneous expenses : 



Engineering $164. 83 



Clearing right of way 282. 70 



Rebuilding bridges '. 104. 96 



Incidentals 48. 77 



Administration 618. 00 



1, 219. 26 



SELECTION OF DREDGE. 



The floating dipper dredge is admirably adapted to the excavation 

 of drainage ditches having sufficient width and depth and the neces- 

 sary supply of water for floating the machine, and especially where 

 the ground is swampy or covered with trees or stumps, rendering 

 impracticable the use of teams or of so-called dry-land machinery. 

 No other type of excavator is so well fitted for digging ditches in a 

 timbered country or where large stumps will be encountered. The 

 dipper dredge, however, is not well adapted to digging channels of 

 less than 100 square feet cross section. Standard types of dipper 

 dredges are not adapted to digging ditches more than 1,200 square 

 feet in cross section, although most makers will build special machines 

 for larger ditches. As ordinarily operated, the dipper dredge con- 

 structs a more or less ragged and irregular ditch, but in the hands 

 of a skilled . operator very good results can be obtained. 



The size of dredge that should be used depends upon various fac- 

 tors. Not only the greatest and least, but also the intermediate 

 cross-sectional dimensions of the proposed ditch should be known, 

 and the relative amount of each class. The specified width of berm 

 and the side slopes should also be known. The total amount of exca- 

 vation, the nature of the material, and whether the dirt is to be 

 dumped on one or both sides, are factors that must be considered. 

 A knowledge of the depth of water which can be maintained at a 

 minimum expense is also necessary, and information as to the num- 



